feat: enhance login tracking and logout functionality

- Added session storage flag to track local login success, ensuring OAuth flows do not double track login events.
- Implemented tracking for logout events in both UserDropdown and AppSidebar components, resetting PostHog identity accordingly.
- Minor formatting adjustments in GoogleLoginButton and footer-new components for consistency.

surfsense_web/app/(home)/login/GoogleLoginButton.tsx

@@ -14,7 +14,7 @@ export function GoogleLoginButton() {
 		trackLoginAttempt("google");
 
 		// IMPORTANT: Use the redirect-based authorize endpoint for cross-origin OAuth
-		// This fixes CSRF cookie issues in Firefox/Safari where cookies set via 
+		// This fixes CSRF cookie issues in Firefox/Safari where cookies set via
 		// cross-origin fetch requests may not be sent on subsequent redirects.
 		// The authorize-redirect endpoint does a server-side redirect to Google
 		// and sets the CSRF cookie properly for same-site context.

surfsense_web/app/(home)/login/LocalLoginForm.tsx

@@ -54,6 +54,11 @@ export function LocalLoginForm() {
 			// Track successful login
 			trackLoginSuccess("local");
 
+			// Set flag so TokenHandler knows local login was already tracked
+			if (typeof window !== "undefined") {
+				sessionStorage.setItem("login_success_tracked", "true");
+			}
+
 			// Success toast
 			toast.success(t("login_success"), {
 				id: loadingToast,